Make 'utils.monkey_patch' py3 compatible
Make 'utils.monkey_patch' py3 compatible

'utils.monkey_patch' function uses py2-specific thing - 'inspect.ismethod'
for getting list of class method members. But the concept of 'unbound methods'
has been removed from the python 3.x and 'methods' now are the same type as
standalone functions.
So, add such distinguish to 'utils.monkey_patch' function
to make it py 2/3 compatible.

Change-Id: I24927e72e72e06105ee7be64c17b7b68214216e0
Partially-Implements: bp py3-compatibility

vponomaryov/manila,NetApp/manila,bswartz/manila,scality/manila,sajuptpm/manila,vponomaryov/manila,openstack/manila,redhat-openstack/manila,redhat-openstack/manila,sajuptpm/manila,scality/manila,jcsp/manila,NetApp/manila,jcsp/manila,bswartz/manila,openstack/manila